In flat worms fertilization and development
is respectively
(A) Internal, indirect
(B) Internal, direct
(C) External, indirect
(D) External, direct
Answers
Answer:
Flat worm are bisexual and fertilization is internal, development is indirect through many larval stages.
so, A. is the correct answer
Answer:
the correct answer is (A) Internal, indirect
Explanation:
In flatworms fertilization and development
is respectively Internal, indirect
Sponge development often occurs indirectly and internally. Inside the female body, trapped sperm are intermediated to eggs before internal fertilisation. Basal animals include the family phylum Porifera of sponges. Multicellular creatures make up sponges. They exhibit circular symmetry. Their diffusion relies on their respiratory system.
The growth of the enteropneust hemichordate Balanoglossus misakiensis, from fertilisation to transformation. This is the first publication to detail the whole laboratory development of an indirect-developing hemichordate. By raising the temperature of saltwater from 23 to 28 degrees C, mature adults were made to spawn. Eggs (200 microns in diameter) had a non-mucilaginous membrane around them and were easily distributed in saltwater. The first and second polar bodies formed inside the fertilisation envelope after artificial insemination, which raised the envelope from the egg surface beneath the egg membrane. After fertilisation, zygotes split into blastulae at intervals of 20 minutes, and gastrulation began 9 hours later. One day after fertilisation, embryos developed into the normal feeding tornaria larvae. The larvae changed 7–10 days. without going through the first or fourth stages of indirect-developing hemichordate development. following fertilisation. Non-fed larvae did not undergo metamorphosis. Within a week of settling in the sand at the bottom of the culture tube, the juveniles had finished developing their adult bodies.
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